Your test is biased in that it assumes all historians only care about the aftermath, when there's plenty of them that care about how the battles themselves played out, along with the past that lead up to it.

There are some. But not many, and especially not many professional historians. Military history is very much a niche field at this point.

Specifically, getting a clearer picture of those battles give us a clearer picture of everything surrounding it, including the past.

I would disagree with this point, as would others I think. That's why military history is largely seen as being a mostly unproductive field.

In your simple test, was Alexander lucky to be born in a time when the Macedonian phalanx was unbeatable, or was he intelligent enough to make it work?

This assumes it was unbeatable, and that he was just lucky enough to fight people that were either too stupid to fight back against it or people who could fight back against it, but lacked sufficient manpower to do so, etc.

At the end of the day, it doesn't matter though. He won. That matters. How he won changes little to nothing as far as I can tell. Feel free to dispute.

The answer to this allows us to add evidence as to whether Macedonia used cavalry effectively or not.

Which I would argue is a question that is equally as useless in studying history.

You can't just say, "Well, we already know they used cavalry from other sources". It's ALWAYS better to have more evidence that points to a picture that we can agree on.

I suppose--but I'm not seeing how this question is historically useful one way or another. I'm sure it's interesting to someone. But that's not really the standard that I would use for judging something worthwhile of historical study.